Hot melt inks

ABSTRACT

A method for forming a mark on a substrate is disclosed. The method includes: (a) heating an edible hot melt ink including a colorant to a temperature sufficient to liquify the ink; and (b) transferring the ink to a substrate to provide a mark on the substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation under 35 U.S.C. §120 of U.S.application Ser. No. 10/498,103, filed Dec. 27, 2004, which is theNational Stage Application under 35 U.S.C. §371 of InternationalApplication No. PCT/US2002/37446, filed on Nov. 21, 2002, which claimspriority to U.S. patent application Ser. No. 10/005,015, filed on Dec.4, 2001, which is now abandoned. The contents of these applications areincorporated herein by reference in their entirety.

BACKGROUND

This invention relates to hot melt inks.

Hot melt inks are solid at room temperature and liquid at temperaturesabove room temperature. Hot melt inks can be used, for example, indigital to print methods. During printing, the ink is heated until itbecomes liquid, and is then ejected through a printhead onto asubstrate. The ink then solidifies on the substrate.

Hot melt inks have been be used, for example, on food packaging.However, it is sometimes desirable to mark directly onto various foodproducts, such as eggs and cheese.

Marking directly onto foods allows for additional productidentification, as well as the only available identification in caseswhere the product is sold with little to no packaging, or in cases wherethe product is not packaged until the point of sale.

The conventional methods for printing directly onto food productsinclude applying liquid inks through stamping, flexography, gravureprinting, or continuous ink jet printing technologies. Stamping,flexography, and gravure printing are not digital to print, and cansometimes result in poor print quality. Continuous ink jet printing canresult in a mark with low resolution.

SUMMARY

The invention is directed to hot melt inks that are formulated usingedible components. Because the inks are made with edible ingredients,the inks may be used to print directly onto food products such as eggs,fruit, cheese, and confectioneries in compliance with the Federal Food,Drug, and Cosmetic Act, and all other applicable food additiveregulations. In addition, because the inks are approved as direct foodadditives, they are automatically approved for indirect food contact.For example, the inks can be used to print on spice sachets that areincluded in packaged rice and pasta products. The inks can also be usedto print on non-food products such as feminine hygiene product wrappersand hygiene wipes.

Because the inks are hot melt inks, they can be used in digital to printmethods, resulting in higher resolution and improved print qualitycompared to other print methods, such as continuous ink jet printingmethods. The inks have a number of properties that make them suitablefor use on food products. For example, as discussed herein, the inks areedible. In addition, the inks may be formulated such that they canadhere to the irregular surfaces of some food products, e.g., oranges;the inks can also adhere to the moist surfaces of other food products.The inks are formulated such that marks made with the inks can remainlegible, even after being subjected to the conditions, e.g.,refrigeration or freezing, under which many foods are stored.

In one aspect, the invention features a method for forming a mark on afood product; the method includes: (a) heating an edible hot melt inkincluding a colorant to a temperature sufficient to liquify the ink; and(b) transferring the ink to a substrate to provide a mark on the foodproduct. The ink can also include a wax and/or a resin. The mark cancover less than 90% of the surface of the food product; less than 75% ofthe surface of the food product; less than 50% of the surface of thefood product; or less than 25% of the surface of the food product.

In another aspect, the invention features a method for forming a mark ona food product; the method includes: (a) heating a hot melt inkincluding an edible colorant to a temperature sufficient to liquify theink; and (b) transferring the ink to a substrate to provide a mark onthe food product. The resolution of the mark can be at least 50 DPI orat least 75 DPI. The melting temperature of the ink can be less than100° C.; less than 80° C.; less than 60° C.; or less than 50° C.

In another aspect, the invention features a composition including a foodproduct (e.g., an egg, cheese, fruit, or a confectionary); at least aportion of the food product is marked with a hot melt ink. The inkincludes a colorant and consists essentially of edible components. Theink may include a wax.

In another aspect, the invention features a composition including a foodproduct; the food product has a mark formed from a hot melt ink thatincludes an edible colorant. The melting temperature of the ink can beless than 100° C.; less than 80° C.; less than 60° C.; or less than 50°C. The resolution of the mark can be at least 50 DPI or at least 75 DPI.

In yet another aspect, the invention features a hot melt ink including:(a) a wax selected from the group consisting of carnauba wax andbeeswax; and (b) a colorant, wherein the ink consists essentially ofedible components. The ink can include a resin, e.g., a hydrogenatedrosin ester resin. The ink can also include an antioxidant. In addition,the ink can contain about 50% to about 99% by weight wax; about 55% toabout 75% by weight wax; or about 30% to about 50% by weight resin.

In another aspect, the invention features a method for forming a mark ona food product. The method includes: (a) heating a hot melt inkcontaining a colorant to a temperature sufficient to liquify the ink;and (b) transferring the ink to a substrate to provide a mark on thefood product. The ink consists essentially of edible components.

By “edible” in reference to a component is meant that the component islisted as a Generally Recognized as Safe direct food additive (GRAS) insection 21 of the Code of Federal Regulations or is EAFUS-listed, i.e.,included on the on the Food and Drug Administration's list of“everything added to food in the United States.” An “edible ink” is anink that contains less than 100 ppm by weight of any impurities, i.e.,any components that are not listed as GRAS or are not EAFUS-listed.

By “mark” is meant a legible impression, e.g., a series of letters,numbers, and/or symbols, on a substrate. An example of a mark that isoften made on food products is a “Sell by” date.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWING

The FIGURE is a side sectional view of an ink jet printhead.

DETAILED DESCRIPTION

A preferred ink is a hot melt ink that is composed primarily of ediblematerials. An ink that is composed essentially of edible ingredientswill itself be, by definition, edible. Therefore, the ink may be used toform marks directly on food products, and the food products so markedwill remain edible.

The ink may include a wax. The wax provides the ink with the property ofbeing solid at room temperature, but liquid at elevated temperatures.The ink can melt between 40° C. and 100° C., and preferably meltsbetween 40° C. and 60° C. Thus, the ink melts at a temperature that islow enough to avoid cooking or damaging the food substrate when the inkis applied.

The ink should contain enough wax that the ink, as a whole, is a hotmelt material. The ink may also contain combinations of waxes. The inkpreferably contains about 50% to about 99% by weight wax, and morepreferably contains about 55% to about 75% by weight wax.

Examples of waxes include: stearic acid; succinic acid; beeswax;candelilla wax; carnauba wax; alkylene oxide adducts of alkyl alcohols;phosphate esters of alkyl alcohols; alpha alkyl omegahydroxypoly(oxyethylene); allyl nonanoate; allyl octanoate; allylsorbate; allyl tiglate; rice bran wax; paraffin wax; microcrystallinewax; synthetic paraffin wax; synthetic paraffin and succinicderivatives; petroleum wax; synthetic petroleum wax; cocoa butter;diacetyl tartaric acid esters of mono and diglycerides; mono anddiglycerides; alpha butyl omegahydroxypoly(oxyethylene)poly(oxypropylene); calcium pantothenate; fattyacids; organic esters of fatty acids; calcium salts of fatty acids; mono& diesters of fatty acids; sucrose fatty acid esters; calciumstearoly-2-lactylate; Japan wax; lanolin; glyceryl hydroxydecanoate;glyceryl hydroxydodecanoate; oxidatively refined montan wax fattyacids,; polyhydric alcohol diesters; oleic acids; palmitic acid;d-pantothenamide; polyethylene glycol (400) dioleate; polyethyleneglycol (MW 200-9,500); polyethylene (MW 200-21,000); oxidizedpolyethylene; polyglycerol esters of fatty acids; polyglyceryl phthalateester of coconut oil fatty acids; shellac wax; hydroxylated soybean oilfatty acids; stearyl alcohol; and tallow and its derivatives.

Preferred waxes include #1 Yellow Carnauba wax and White Beeswax, bothavailable from Koster Keunen.

The ink may include a resin. The resin provides the ink with a desiredviscosity, thermal stability, flexibility, and adhesion properties. Theink should include enough resin to achieve the desired viscosity,stability, flexibility, and adhesion. Preferably, the ink contains about0% to about 50% by weight resin, and more preferably contains about 30%to about 50% by weight resin.

Examples of resins include acacia (gum arabic); gum ghatti; guar gum;locust (carob) bean gum; karaya gum (sterculia gum); gum tragacanth;chicle; highly stabilized rosin ester; tall oil; manila copais; corngluten; coumarone-indene resins; crown gum; damar gum; p,alpha-dimethylstyrene; gum elemi; ethylene oxide polymer and itsadducts; ethylene oxide/propylene oxide copolymer and its adducts;galbanum resin; gellan gum; ghatti gum; gluten gum; guaiac gum; guaranagum; heptyl paraben; cellulose resins, including methyl andhydroxypropyl; hydroxypropyl methylcellulose resins;isobutylene-isoprene copolymer; mastic gum; oat gum; opopanax gum;polyacrylamide; modified polyacrylamide resin; polylimonene;polyisobutylene (min. MW 37,000); polymaleic acid; polyoxyethylenederivatives; polypropylene glycol (MW 1200-3000); polyvinyl acetate;polyvinyl alcohol; polyvinyl polypyrrolidone; polyvinyl pyrrolidone;rosin, adduct with fumaric acid, pentaerythritol ester; rosin, gum,glycerol ester; rosin, gum or wood, pentaerythritol ester; rosin, gum orwood, partially hydrogenated, glycerol ester; rosin, gum or wood,partially hydrogenated, pentaerythritol ester; rosin, methyl ester,partially hydrogenated; rosin, partially dimerized, glycerol ester;rosin, partially hydrogenated; rosin and rosin derivatives; rosin,polymerized, glycerol ester; rosin, tall oil, glycerol ester; rosin,wood; rosin, wood, glycerol ester; purified shellac; styrene; styreneterpolymers; styrene copolymers; sucrose acetate isobutyrate; terpeneresins, natural and synthetic; turpentine gum; vinylacetate; vinylchloride-vinylidene chloride copolymer; zanthan gum; and zein.

A preferred resin is Foral 85 hydrogenated rosin ester resin, availablefrom Hercules.

The ink may include a colorant or dye, which provides color to the ink.If an ink is to be used on a white or light-colored food product, it isdesirable for the ink to have a dark color, for better legibility of themark. If an ink is to be used on a dark-colored food product, it may notbe necessary to include a colorant in the ink. The ink preferablycontains a sufficient amount of the colorant that the ink has color, butnot so much as to interfere with other desirable qualities, such as hotmelt qualities or viscosity. Preferred inks contain about 0.1% to about20% by weight colorant, and more preferably contain about 1% to about10% by weight colorant.

Examples of colorants include beta carotene; b-apo-8′-carotenal;canthaxanthin; astaxanthin; brown algae extract; red algae; red algaeextract; allspice oleoresin; FD&C Green no. 3; FD&C Green no. 3,aluminum lake; FD&C Green no. 3, calcium lake; FD&C Blue no. 1; FD&CBlue no. 2; FD&C Blue no. 1, aluminum lake; FD&C Blue no. 2, aluminumlake; FD&C Blue no. 1, calcium lake; FD&C Blue no. 2, calcium lake; FD&CRed no. 40; FD&C Red no. 40, calcium lake; FD&C Yellow no. 6; FD&CYellow no. 5, aluminum lake; FD&C Yellow no. 5, calcium lake; FD&CYellow no. 6, aluminum lake; FD&C Yellow no. 6, calcium lake; ironoxide; citrus red no. 2; titanium dioxide; turmeric oleoresin;ultramarine blue; carmine; caramel; channel black; FD&C Green no. 3;FD&C Red, no. 3; FD&C Yellow, no. 6; Ponceau 4R; quinoline yellow;patent blue V; Green S; Brown HT; brilliant black BN; carmoisine;amaranth; erythrosine late; amaranth lake; Ponceau 4R lake; andcarmoisine lake. A preferred colorant is Apocarotenal.

The ink may include a stabilizer, which inhibits oxidation of the inkcomponents. Sufficient stabilizer should be included to inhibitoxidation, but not so much should be included that the other propertiesof the ink are adversely affected. The ink preferably includes about0.1% to about 2% by weight stabilizer, and more preferably containsabout 0.5% to about 1% by weight stabilizer.

Examples of stabilizers include butylated hydroxyanisole (BHA);butylated hydoxytoluene (BHT); propyl gallate; tert-butyl hydroquinone(TBHQ); ethylenediaminetetraacetic acid (EDTA); methyl paraben; propylparaben; benzoic acid. A preferred stabilizer is Tenox BHA, availablefrom Eastman Chemical.

The ink may include a dispersant and/or a surface tension modifier. Asufficient quantity of these optional ingredients may be included in theink to provide the desired property, e.g., the desired surface tension.The ink preferably includes about 0.5% to about 5% by weight dispersantor surface tension modifier, and more preferably contains about 0.2% toabout 1% by weight dispersant or surface tension modifier. An example ofa dispersant and/or surface tension modifier is lecithin.

Additionally, the ink may include other conventional hot melt inkingredients such as oils, flexibilizers, plasticizers, and otheradditives. Oils, flexibilizers, and plasticizers can reduce theviscosity of the inks. A sufficient quantity of these optionalingredients may be included in the ink to provide the desired viscosity.

Examples of oils, flexibilizers and plasticizers include glycerin;lecithin and modified lecithins; agar-agar; dextrin; diacetyl; enzymemodified fats; glucono delta-lactone; carrot oil; chincona extract;rapeseed oil; pectins; propylene glycol; peanut oil; sorbitol;acetophenone; brominated vegetable oil; polyoxyethylene 60 sorbitan monostearate; olestra; castor oil; oiticia oil; 1,3 butylene glycol; coconutoil and its derivatives; corn oil; substituted benzoates; substitutedbutyrates; substituted citrates; substituted formates; substitutedhexanoates; substituted isovalerates; substituted lactates; substitutedpropionates; substituted isobutyrates; substituted octanoates;substituted palmitates; substituted myristates; substituted oleates;substituted stearates, distearates and tristearates; substitutedgluconates; substituted undecanoates; substituted behenates; substitutedsuccinates; substituted gallates; substituted heptanoates; substitutedphenylacetates; substituted cinnamates; substituted 2-methylbutyrates;substituted tiglates; corn syrup; isoparaffinic petroleum hydrocarbons;mineral oil; glycerin; mono- and diglycerides and their derivatives;olibanum oil; opopanax oil; peanut oil; polysorbates 20, 60, 65, 80;propylene glycol mono- and diesters of fats and fatty acids; epoxidizedsoybean oil; hydrogenated soybean oil; sperm oil; and hydrogenated spermoil.

The inks generally are prepared by combining all of the ink ingredientsexcept for the colorant; heating the resulting combination to atemperature above its melting point; and slowly stirring until theliquified combination is homogeneous. If a colorant is to be included,it is then added to the mixture with stirring, or dispersed into themolten materials. The molten ink is filtered to remove particles largerthan 1 μm in size.

The preferred inks can be used with a conventional hot melt ink jetprinter. Referring to the FIGURE, the printhead 10 of this printerincludes a fill port 12, a membrane cavity 14, a pumping chamber 16, aPZT (piezoelectric transducer) 18, and an orifice 20. The ink is placedin the printhead through the fill port 12; the ink then passes throughthe membrane cavity 14, where is it degassed. The ink then flows intothe pumping chamber 16. The printhead 10 is heated, so the ink is meltedto a liquid state prior to being ejected from the ink jet printhead. Theliquid ink is ejected by activation of the PZT 18. This printer is knownas a drop on demand printer since a droplet of ink is ejected each timethe PZT material is activated. Drop on demand printers are described inmore detail in U.S. Pat. No. 5,265,315, which is hereby incorporated byreference in its entirety. An example of a printer that can be used isthe Markem 9096 printer, which has 96 ink jet orifices and a resolutionof 96 DPI. In the 9096 printer, actuation of the PZT element associatedwith each orifice is digitally controlled.

During printing, as a substrate passes by the orifices 20, droplets ofthe hot, liquid ink are ejected through the orifices. Upon contactingthe substrate, which is typically at room temperature or below roomtemperature, the liquid ink cools and solidifies.

The inks may be used to form marks on foods, or on other substrates. Forexample, the inks may be used to form marks on cheese, eggs,confectioneries, etc. The ink to be used will depend on the adhesion,abrasion resistance, and packaging requirements of the food or non-foodproduct.

The preferred inks do not render the food products marked with the inksinedible. In other words, compositions containing a food product and apreferred ink are edible. An example of such a composition is a piece ofcheese marked with an edible hot melt ink.

The following examples are meant to illustrate the invention, and arenot to be construed as limiting the following claims.

EXAMPLE 1

A hot melt ink was prepared that included: 48% by weight #1 YellowCarnauba wax; 4% by weight White Beeswax; 37.5% by weight Foral 85hydrogenated rosin ester resin; 0.5% by weight Tenox BHA; and 10% byweight Apocarotenal dispersion 20A.

EXAMPLE 2

A hot melt ink was prepared that included: 48% by weight #1 YellowCarnauba wax; 4% by weight NF Beeswax; 37.5% by weight Foral 85hydrogenated rosin ester resin; 0.5% by weight Tenox BHA; and 10% byweight Apocarotenal dispersion 20A.

EXAMPLE 3

A hot melt ink was prepared that included: 52.25% by weight #1 YellowCarnauba wax; 42.75% by weight Foral 85 hydrogenated rosin ester resin;5% by weight Apocarotenal dispersion 20A. The viscosity of this ink at135° C. is 22.4 centipoise.

EXAMPLE 4

A hot melt ink was prepared that included: 42% by weight Foral 85hydrogenated rosin ester resin; 28% by weight #1 Yellow Carnauba wax;24% by weight Hercolyn D hydrogenated rosin ester resin; and 6% byweight Apocarotenal dispersion 20A. The viscosity of the ink at 135° C.is 22.4 centipoise.

These inks may be modified in order to change desired properties. Forexample, Yellow Carnauba Wax is relatively hard, and beeswax isrelatively soft. Changing the ratio of carnauba wax to beeswax to alterthe flex and adhesion properties of the inks. Alternatively, arelatively hard resin could be replaced by a relatively soft resin tochange flex and adhesion properties.

All publications and patents mentioned in this application are hereinincorporated by reference to the same extent as if each individualpublication or patent was specifically and individually indicated to beincorporated by reference.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

1. A method of forming a mark, the method comprising: heating an ediblehot melt ink to a temperature sufficient to liquefy the ink; andejecting droplets of the melted ink from a pumping chamber of adrop-on-demand piezoelectric inkjet printhead to form a mark upon thesurface of a substrate, the mark having a resolution of at least 50 dpi;wherein the ink is completely edible and comprises an edible wax and isfree of succinic acid and its derivatives; and wherein the ink has amelting temperature of between 40° C. and 100° C.
 2. The method of claim1, wherein the substrate is a food product.
 3. The method of claim 1,wherein the wax is selected from the group consisting of: carnauba wax;beeswax; alkylene oxide adducts of alkyl alcohols; phosphate esters ofalkyl alcohols; alpha alkyl omega hydroxypoly(oxyethylene); allylnonanoate; allyl octanoate; allyl sorbate; allyl tiglate; rice bran wax;petroleum wax; synthetic petroleum wax; cocoa butter; diacetyl tartaricacid esters of mono and diglycerides; mono and diglycerides; alpha butylomega hydroxypoly(oxyethylene) poly(oxypropylene); calcium pantothenate;fatty acids; organic esters of fatty acids; calcium salts of fattyacids; mono & diesters of fatty acids; sucrose fatty acid esters;calcium stearoyl-2-lactylate; Japan wax; lanolin; glycerylhydroxydecanoate; glyceryl hydroxydodecanoate; oxidatively refinedmontan wax fatty acids; polyhydric alcohol diesters; oleic acids;palmitic acid; d-pantothenamide; polyethylene glycol (400) dioleate;polyglycerol esters of fatty acids; polyglyceryl phthalate ester ofcoconut oil fatty acids; shellac wax; hydroxylated soybean oil fattyacids; stearyl alcohol; tallow; tallow derivatives, and any combinationsthereof.
 4. The method of claim 1, wherein the wax is carnauba wax orbeeswax.
 5. The method of claim 1, wherein the mark covers less than 90%of the surface.
 6. The method of claim 1, wherein the mark covers lessthan 75% of the surface.
 7. The method of claim 1, wherein the markcovers less than 50% of the surface.
 8. The method of claim 1, whereinthe mark covers less than 25% of the surface.
 9. The method of claim 1,wherein the ink comprises 50% to 99% by weight wax.
 10. The method ofclaim 1, wherein the resolution is at least 75 dpi.
 11. The method ofclaim 1, wherein ink further comprises an edible colorant.
 12. Themethod of claim 1, wherein ink further comprises an edible resin. 13.The method of claim 1, wherein the ink further comprises less than 50%by weight of an edible resin.
 14. The method of claim 12, wherein theink comprises 30% to 50% by weight edible resin.
 15. A method of forminga mark, the method comprising: heating an edible hot melt ink to atemperature sufficient to liquefy the ink; and ejecting droplets of themelted ink from a pumping chamber of a drop-on-demand piezoelectricinkjet printhead to form a mark upon the surface of a substrate, themark having a resolution of at least 50 dpi; wherein the ink iscompletely edible and comprises an edible wax and an edible colorant,the edible hot melt ink being free of succinic acid and its derivatives;and wherein the ink has a melting temperature of between 40° C. and 100°C.
 16. The method of claim 15, wherein the substrate is a food product.17. The method of claim 15, wherein the wax is selected from the groupconsisting of: carnauba wax; beeswax; alkylene oxide adducts of alkylalcohols; phosphate esters of alkyl alcohols; alpha alkyl omegahydroxypoly(oxyethylene); allyl nonanoate; allyl octanoate; allylsorbate; allyl tiglate; rice bran wax; petroleum wax; syntheticpetroleum wax; cocoa butter; diacetyl tartaric acid esters of mono anddiglycerides; mono and diglycerides; alpha butyl omegahydroxypoly(oxyethylene) poly(oxypropylene); calcium pantothenate; fattyacids; organic esters of fatty acids; calcium salts of fatty acids; mono& diesters of fatty acids; sucrose fatty acid esters; calciumstearoyl-2-lactylate; Japan wax; lanolin; glyceryl hydroxydecanoate;glyceryl hydroxydodecanoate; oxidatively refined montan wax fatty acids;polyhydric alcohol diesters; oleic acids; palmitic acid;d-pantothenamide; polyethylene glycol (400) dioleate; polyglycerolesters of fatty acids; polyglyceryl phthalate ester of coconut oil fattyacids; shellac wax; hydroxylated soybean oil fatty acids; stearylalcohol; tallow; tallow derivatives, and any combinations thereof. 18.The method of claim 15, wherein the wax is carnauba wax or beeswax. 19.The method of claim 15, wherein the mark covers less than 90% of thesurface.
 20. The method of claim 15, wherein the mark covers less than75% of the surface.
 21. The method of claim 15, wherein the mark coversless than 50% of the surface.
 22. The method of claim 15, wherein themark covers less than 25% of the surface.
 23. The method of claim 15,wherein the ink comprises 50% to 99% by weight wax.
 24. The method ofclaim 15, wherein the resolution is at least 75 dpi.
 25. The method ofclaim 15, wherein ink further comprises an edible resin.
 26. The methodof claim 15, wherein the ink further comprises less than 50% by weightof an edible resin.
 27. The method of claim 15, wherein the inkcomprises 30% to 50% by weight edible resin.
 28. A method of forming amark, the method comprising: heating an edible hot melt ink to atemperature sufficient to liquefy the ink; and ejecting droplets of themelted ink from a pumping chamber of a drop-on-demand piezoelectricinkjet printhead to form a mark upon the surface of a substrate, themark having a resolution of at least 50 dpi; wherein the ink iscompletely edible and comprises an edible wax selected from the group ofcarnauba wax and beeswax, and an edible colorant, the edible hot meltink being free of succinic acid and its derivatives; and wherein the inkhas a melting temperature of between 40° C. and 100° C.
 29. Acomposition of matter comprising a substrate, wherein at least a portionof the substrate is marked with an edible hot melt ink, the ink beingcompletely edible and comprising an edible wax and an edible colorant,the edible hot melt ink being free of succinic acid and its derivatives.30. The composition of claim 29, wherein the edible wax is carnauba waxor beeswax.
 31. A method of forming a mark, the method comprising:heating an edible hot melt ink to a temperature sufficient to liquefythe ink; and ejecting droplets of the melted ink from a pumping chamberof a drop-on-demand piezoelectric inkjet printhead to form a mark uponthe surface of a substrate, the mark having a resolution of at least 50dpi; wherein the ink is completely edible and comprises an edible wax,the edible hot melt ink being free of succinic acid and its derivatives;wherein the ink has a melting temperature of between 40° C. and 100° C.;and, wherein the wax is selected from the group consisting of: carnaubawax; beeswax; alkylene oxide adducts of alkyl alcohols; phosphate estersof alkyl alcohols; alpha alkyl omega hydroxypoly(oxyethylene); allylnonanoate; allyl octanoate; allyl sorbate; allyl tiglate; rice bran wax;petroleum wax; synthetic petroleum wax; cocoa butter; diacetyl tartaricacid esters of mono and diglycerides; mono and diglycerides; alpha butylomega hydroxypoly(oxyethylene) poly(oxypropylene); calcium pantothenate;fatty acids; organic esters of fatty acids; calcium salts of fattyacids; mono & diesters of fatty acids; sucrose fatty acid esters;calcium stearoyl-2-lactylate; Japan wax; lanolin; glycerylhydroxydecanoate; glyceryl hydroxydodecanoate; oxidatively refinedmontan wax fatty acids; polyhydric alcohol diesters; oleic acids;palmitic acid; d-pantothenamide; polyethylene glycol (400) dioleate;polyglycerol esters of fatty acids; polyglyceryl phthalate ester ofcoconut oil fatty acids; shellac wax; hydroxylated soybean oil fattyacids; stearyl alcohol; tallow; tallow derivatives, and any combinationsthereof.
 32. A composition of matter comprising a substrate, wherein atleast a portion of the surface of the substrate is marked with an ediblehot melt ink, the ink being completely edible and comprising an edibleresin, an edible wax and an edible colorant, the edible hot melt inkbeing free of succinic acid and its derivatives.